PT  - JOURNAL ARTICLE
AU  - Pawel Roszak
AU  - Jung-ok Heo
AU  - Bernhard Blob
AU  - Koichi Toyokura
AU  - Maria Angels de Luis Balaguer
AU  - Winnie W. Y. Lau
AU  - Fiona Hamey
AU  - Jacopo Cirrone
AU  - Xin Wang
AU  - Robertas Ursache
AU  - Hugo Tavares
AU  - Kevin Verstaen
AU  - Jos Wendrich
AU  - Charles W. Melnyk
AU  - Dennis Shasha
AU  - Sebastian E. Ahnert
AU  - Yvan Saeys
AU  - Bert De Rybel
AU  - Renze Heidstra
AU  - Ben Scheres
AU  - Ari Pekka Mähönen
AU  - Berthold Göttgens
AU  - Rosangela Sozzani
AU  - Kenneth D. Birnbaum
AU  - Yrjö Helariutta
TI  - Analysis of phloem trajectory links tissue maturation to cell specialization
AID  - 10.1101/2021.01.18.427084
DP  - 2021 Jan 01
TA  - bioRxiv
PG  - 2021.01.18.427084
4099  - http://biorxiv.org/content/early/2021/01/19/2021.01.18.427084.short
4100  - http://biorxiv.org/content/early/2021/01/19/2021.01.18.427084.full
AB  - The mechanisms that allow cells in the plant meristem to coordinate tissue-wide maturation gradients with specialized cell networks are critical for indeterminate growth. Here, we reconstructed the protophloem developmental trajectory of 19 cells from cell birth to terminal differentiation at single cell resolution in the Arabidopsis root. We found that cellular specification is mediated near the stem cell niche by PHLOEM EARLY DOF (PEAR) transcription factors. However, the PEAR dependent differentiation program is repressed by a broad gradient of PLETHORA (PLT) transcription factors, which directly inhibit PEARs’ own direct target ALTERED PHLOEM DEVELOPMENT (APL). The dissipation of PLT gradient around 7 cells from the stem cell activates APL expression, and a subsequent transitional network that results in a “seesaw” pattern of mutual inhibition over developmental time. Together, we provide a mechanistic understanding of how morphogen-like maturation gradients interface with cell-type specific transcriptional regulators to stage cellular differentiation.Competing Interest StatementThe authors have declared no competing interest.